Electrocatalysis of the oxidation of antimony(III) at platinum electrodes in 2M hydrogen chloride by adsorbed iodide

Determination of antimony using forced-flow liquid chromatography with a coulometric detector

“…The plot has a limiting plateau for 0.70 V < E < 0.90 V which is consistent with I-E curves shown in Ref. (7). A potential of 0.800 V was chosen for use in all succeeding studies.…”

“…The eluent front for 2M HCI required a longer time to reach the detector than the front for the sample because the volume of the stream between the eluent selector valve and the detector was greater than the volume between the sample injection valve and detector [see Figure 1 in Ref. (7)]. The internal volume of the flow meter alone is estimated to be approximately 0.4 ml.…”

“…A large number of chemical species interfere in the determination. More recently, Davenport and Johnson (7) discovered that the highly irreversible electrooxidation of Sb (III) at a platinum electrode in dilute HCI is electrocatalyzed by I" specifically adsorbed at the electrode surface. The choice of supporting electrolyte is important; the anodic process is not electrocatalyzed in H2SC>4 or HCIO4.…”

Chromatographic determination of chromium(VI) with coulometric detection based on the electrocatalysis by adsorbed iodine of the reduction at platinum electrodes in acidic solutions

“…trodes. Davenport and Johnson (15) reported the electrocatalysis of the irreversible oxidation of Sb(III) by adsorbed I and Taylor and Johnson (3) applied the electrocatalyzed reaction for determination of Sb(III) by liquid chromatography with coulometric detection. Lane and Hubbard (16) reported the electrocatalysis of the oxidation of ascorbic acid by adsorbed I at a Pt electrode.…”

Why halides enhance heterogeneous metal ion charge transfer reactions

“…For example, heterogeneous charge transfer reactions including V 2+ /V 3+ , 5,6 Cr 2+ /Cr 3+ , 7,8 Fe 2+ /Fe 3+ , 9,10 and Eu 2+ /Eu 3+ , 11 and metal electrodeposition reactions, such as Cd 0 /Cd 2+ and Zn 0 /Zn 2+ , 12,13 show rate constants (k) that are up to 10 3 higher in the presence of chloride (Cl À ), bromide (Br À ), or iodide (I À ). Kinetic enhancement by halides is observed on many electrodes, including glassy carbon (GC), 14 Hg, 15 Au, 7,10 and Pt, 9,16 where the increase in k typically is the largest for I À , followed by Br À , and then Cl À . Thus, understanding the cause of these enhancements would guide electrolyte and electrode selection.…”